Synthetic-resin screw cap

ABSTRACT

The object of the present invention is to provide a screw cap made of a synthetic resin that always exhibits a reliable stable function of preventing unjust unsealing. 
     It includes: a cap main body ( 2 A) serving as a cap section, a cylindrical wall ( 3 A) of which is closely screwed on a bottle mouth cylinder ( 18 ) constituting a pour spout of the bottle for closely fitting thereon; and a sealing ring ( 11 ) having a second locking section ( 12 ) locked from below across a first locking section ( 20 A) formed around the outer peripheral surface of the bottle mouth cylinder ( 18 ) and connected to the lower end of the cylindrical wall ( 3 ) through a plurality of easily breakable pieces ( 7 ), wherein a plurality of second pressing slopes ( 14 ) is disposed on the upper end of the sealing ring ( 11 ) so that the plurality of second pressing slope is closely opposed to a plurality of first pressing slopes ( 9 ) disposed on the lower end of the cylindrical wall ( 3 ) so as to slidably abut against the plurality of first pressing slope from an unscrewing direction and at a tilt angle (b) that is a larger acute angle than the lead angle (a) of a helical ridge ( 19 A) of the bottle mouth cylinder ( 18 ), thereby forcibly depressing the sealing ring ( 11 ) by abutment between both the pressing slopes during the unscrewing operation of the cap main body.

TECHNICAL FIELD

The present invention relates to a screw cap made of a synthetic resinwith a function of preventing unjust unsealing, which is joined to apour spout of a bottle and serves as a closable cap.

BACKGROUND ART

Related art techniques of a cap having an unjust-unsealing preventingfunction (pilfer-proof function) include a technique disclosed inJapanese Examined Utility Model Registration Application Publication No.1995-12294.

This related art exhibits the pilfer-proof function in such a way that:a pour spout that is opened and closed by a hinged upper lid is formed;an inner lid made of a metal plate for covering to close the opening ofa bottle mouth cylinder is joined to a lid main body detachably screwedon the bottle mouth cylinder to form a lid; a break line is formed atthe lower end of a skirted wall of the lid main body; the skirted wallis divided into an upper main section and a lower pilfer-proof basesection; the main section and the pilfer-proof base section areconnected with a plurality of breakable ribs; and a locking protrusionis provided on the inner face of the pilfer-proof base section, which islocked from below across a ring-shaped locking jaw of the bottle mouthcylinder.

In this related art, the lid main body must be unscrewed from the bottlemouth cylinder when the inner lid is removed to unseal the bottle first;however, the rib is broken by the unscrewing of the lid main body fromthe bottle mouth cylinder, so that the pilfer-proof base section isseparated from the main body to drop to the lower part of the bottlemouth cylinder. Accordingly, with the lid main body mounted on thebottle mouth cylinder after the inner lid has been removed, thepilfer-proof base section is apart from the mounted lid main body; thus,it can be determined that the bottle has already been unsealed at thesight of this separated state.

DISCLOSURE OF INVENTION

A first invention comprises: a cap section closely screwed with acylindrical wall section to be fitted on a pour spout of a bottle havinga helical ridge cut in the outer peripheral surface; and a sealing ringhaving a second locking section to be locked from below across a firstlocking section, on the inner peripheral surface, the first lockingsection being formed around the outer peripheral surface of the pourspout positioned lower than the helical ridge with the outer endpositioned outside the helical ridge, and the sealing ring beingintegrally connected to the lower end of the cylindrical wall section ofthe cap section through a plurality of easily breakable pieces, whereina plurality of second pressing slopes is disposed on the upper end ofthe sealing ring so that the plurality of second pressing slope isclosely opposed to a plurality of first pressing slopes disposed at thelower end of the cylindrical wall section of the cap section so as toslidably abut against the plurality of first pressing slope from anunscrewing direction and at a tilt angle that is a larger acute anglethan the lead angle of the helical ridge of the pour spout constructingthe function of screwing the pour spout of the bottle and the capsection together.

With the cap section of the screw cap joined to the limit of joining thehelical ridge provided at the pour spout of the bottle, the cap sectionclosely seals the pour spout, and the sealing ring integrally connectedto the lower end of the cylindrical wall section of the cap sectionthrough the breakable pieces locks from below its second locking sectionto the first locking section formed at the outer peripheral surface ofthe pour spout.

When the cap section is unscrewed from this state, the sealing ringcannot be moved upwards relative to the cylindrical wall section, whichmoves upwards, by the locking of the first locking section and thesecond locking section; thus, the breakable pieces are broken.

By the breaking of the breakable pieces, the sealing ring normally dropsand displaces due to its own weight; however, when the sealing ring doesnot drop by adhering to the pour spout, the first pressing slopes of thecylindrical wall section abut against the second pressing slopes of thesealing ring at the same time as the breaking of the breakable pieces orimmediately thereafter, and both the pressing slopes are brought intocontact with each other at a tilt angle that is a larger acute anglethan the lead angle of the helical ridge of the pour spout and thehelical ridge of the cap section. Therefore, the sealing ring isforcibly pushed down by the cylindrical wall section and then surelydrops owing to its own weight.

Accordingly, a reliable stable pilfer-proof function can always beexhibited.

Also, since the sealing ring can forcibly be moved downwards anddisplaced by the unscrewing operation itself of the cap section, theoperation is reliable and simple.

A second invention with the arrangement of the synthetic-resin screw capaccording to the first invention comprises: a cap main body serving as acylindrical cap section with a top, which is closely screwed with acylindrical wall serving as a cylindrical wall section to be fitted on abottle mouth cylinder serving as a pour spout having a helical ridge cutin the outer peripheral surface; and

-   a short cylindrical sealing ring having a second locking section to    be locked from below across a first locking section, on the inner    peripheral surface, the first locking section being formed around    the outer peripheral surface of the bottle mouth cylinder positioned    lower than the helical ridge with the outer end positioned outside    the helical ridge, and the sealing ring being integrally connected    to the lower end of the cylindrical wall of the cap main body    through a plurality of easily breakable pieces,-   wherein a plurality of second pressing slopes is disposed on the    upper end of the sealing ring so that the plurality of second    pressing slope is closely opposed to a plurality of first pressing    slopes disposed at the lower end of the cylindrical wall of the cap    main body so as to slidably abut against the plurality of first    pressing slope from an unscrewing direction and at a tilt angle that    is a larger acute angle than the lead angle of the helical ridge of    the bottle mouth cylinder.

With the bottle mouth cylinder itself being the pour spout and the capmain body serving as a cap section joined to the limit of screwing thehelical ridge cut in the outer peripheral surface of the bottle mouthcylinder, the cap main body closely seals the bottle mouth cylinder, andthe sealing ring integrally connected to the lower end of thecylindrical wall serving as the cylindrical wall section of the cap mainbody through the breakable pieces locks its second locking section frombelow to the first locking section formed at the outer peripheralsurface of the bottle mouth cylinder.

When the cap main body is unscrewed from this state, the sealing ringcannot be moved upwards by the locking of the first locking section andthe second locking section relative to the cap main body that movesupwards; thus, the breakable pieces are broken.

The first pressing slopes of the cylindrical wall abut against thesecond pressing slopes of the sealing ring at the same time as thebreaking of the breakable pieces or immediately thereafter, and both thepressing slopes are brought into contact with each other at a tilt anglethat is a larger acute angle than the lead angle of the helical ridge ofthe cap main body. Therefore, the sealing ring is forcibly pushed downby the cylindrical wall and then surely drops owing to its own weight.

A third invention with the arrangement of the synthetic-resin screw capaccording to the first invention comprises: a pour-cap main body servingas a pour spout of the bottle, having a attaching cylinder fitted on andover the bottle mouth cylinder and forming a pour spout by being closelyfitted thereon; and

-   an outer cap detachably screwed on the pour-cap main body and    serving as a cylindrical cap section with a top for opening and    closing the pour spout of the pour-cap main body, wherein:-   a first locking section is formed around the outer peripheral    surface of the attaching cylinder of the pour-cap main body;-   a sealing ring is integrally connected through a plurality of    breakable pieces to the lower end of an outer cylinder serving as a    cylindrical wall section of the outer cap to be fitted on the    attaching cylinder of the pour-cap main body in a closed state, the    sealing ring having a second locking section to be locked from below    to the first locking section of the pour-cap main body; and-   a plurality of second pressing slopes is disposed on the upper end    of the sealing ring so that the plurality of second pressing slope    is closely opposed to a plurality of first pressing slopes disposed    on the lower end of the outer cylinder of the outer cap so as to    slidably abut against the plurality of first pressing slope from an    unscrewing direction and at a tilt angle that is a larger acute    angle than the lead angle of the helical ridge of the pour-cap main    body.

The outer cap serving as a cap section screwed on the pour-cap main bodyserving as a pour spout of the bottle, which is fitted on the bottlemouth cylinder, closely seals the pour spout of the pour-cap main body;and the sealing ring of the outer cap fitted on the attaching cylinderof the pour-cap main body locks from below its second locking section tothe first locking section formed at the outer peripheral surface of theattaching cylinder of the pour-cap main body.

When the outer cap is unscrewed from this state, the sealing ring cannotbe moved upwards by the locking of the first locking section and thesecond locking section relative to the outer cylinder constituting thecylindrical wall section of the outer cap that moves upwards; thus, thebreakable pieces are broken. The first pressing slopes of the outercylinder abut against the second pressing slopes of the sealing ring atthe same time as the breaking of the breakable pieces or immediatelythereafter, and both the pressing slopes are brought into contact witheach other at the lead angle of the helical ridge of the pour-cap mainbody, that is, at a tilt angle that is a larger acute angle than thelead angle of a portion constructing the function of screwing thepour-cap main body and the outer cap. Therefore, the sealing ring isforcibly pushed down by the outer cylinder and then surely drops owingto its own weight.

A fourth invention has an arrangement in which the cylindrical wallsection includes first stopping sections in combination with the firstpressing slopes, and the sealing ring includes second stopping sectionsso that they are closely opposed to the first stopping sections so asnot to get over them from the screwing direction in combination with thesecond pressing slopes, in addition to the arrangement of thesynthetic-resin screw cap according to the first, second, or thirdinvention.

In this invention, the sealing ring cannot be turned relative to thecylindrical wall or the outer cylinder constituting the cylindrical wallsection in an unscrewing direction because of the abutment of the secondstopping sections against the first stopping sections, so that theoccurrence of a problem is prevented in advance in that when the sealingring screws the cap main body or the outer cap constituting the capsection to the bottle mouth cylinder or the pour-cap main bodyconstituting the pour spout, the easily breakable pieces are broken.

Also, since the first pressing slopes and the second pressing slopes areprovided using the first stopping sections and the second stoppingsections, the pressing slopes can easily be formed.

A fifth invention has an arrangement in which one of a first combinationof the first stopping sections and the first pressing slopes and asecond combination of the second stopping sections and the secondpressing slopes is formed into a protrusion and the other is formed intoa recess into which the protrusion is inserted, in addition to thearrangement of the synthetic-resin screw cap according to the fourthinvention.

The present invention has a simplified arrangement of the joiningsections of the stopping sections and the pressing slopes, and asimplified opposed arrangement of both stopping sections and bothpressing slopes, thus facilitating molding correspondingly.

A sixth invention has an arrangement in which each of the firstcombinations and the second combinations, one of which is formed into aprotrusion and the other is formed into a recess, is arranged in waveform in the circumferential direction, in addition to the arrangement ofthe synthetic-resin screw cap according to the fifth invention.

In this invention, since the first combination formed at the lower endof the cylindrical wall or the outer cylinder constituting thecylindrical wall section and the second combination formed at the upperend of the sealing ring, which have the same opposed structure, are eacharranged in wave form in the circumferential direction, the shape of thecylindrical wall section and the shape of the upper end of the sealingring have high symmetry; thus, both the stopping sections and both thepressing slopes exhibit the aforesaid function, and improve theappearance.

A seventh invention has an arrangement in which either one of the lowersurface of the cylindrical wall section and the upper surface of thesealing ring has a protrusion extending toward the other for decreasingthe spacing between the cylindrical wall section and the sealing ring,in addition to the arrangement of the synthetic-resin screw capaccording to the first, second, third, fourth, fifth, or sixthinvention.

This invention includes a protrusion for decreasing the spacing betweenthe cylindrical wall or the outer cylinder constituting the cylindricalwall section and the sealing ring; so that when the cap main body or theouter cap constituting the cap section is first screwed on the bottlemouth cylinder or the pour-cap main body constituting the pour spout,the protrusion abuts against the upper surface of the other sealing ringor the lower surface of the cylindrical wall section to ensure a strokebetween the sealing ring and the cylindrical wall section, therebypreventing the easily breakable pieces from bending and broken becauseof a decreased stroke.

Even if the cap main body or the outer cap constituting the cap sectionbends slightly when the cap section is joined to the pour spout, theprotrusion pushes the upper surface of the other sealing ring or thelower surface of the cylindrical wall section; therefore, the secondlocking section provided at the sealing ring of the cap section surelygets over the first locking section formed at the outer peripheralsurface of the pour spout to be locked to the first locking section frombelow.

An eighth invention has an arrangement in which a spacing into which theend of a hard material such as a coin can be inserted is formed betweenthe lower edge of the cylindrical wall serving as a cylindrical wallsection and a neck ring provided at the lower part of the outerperipheral surface of the bottle mouth cylinder, in addition to thearrangement of the synthetic-resin screw cap according to the first,second, fourth, fifth, sixth, or seventh invention.

According to this invention, even a weak person can easily divide thesealing ring from the bottle mouth cylinder by break-opening using afamiliar hard material such as a coin.

A ninth invention has an arrangement in which the width of the sealingring is set to a value at which the lower end almost reaches the neckring of the bottle mouth cylinder with it fitted on the bottle mouthcylinder, in addition to the arrangement of the synthetic-resin screwcap according to the first, third, fourth, fifth, sixth, or seventhinvention.

According to this invention, the spacing formed between the lower edgeof the attaching cylinder of the pour-cap main body and the neck ring isreduced to be minute by almost covering the neck ring with the lower endof the sealing ring; therefore, a hard material such as a coin cannot beinserted into the spacing formed between the lower edge of the attachingcylinder and the neck ring.

Accordingly, unjust division of the pour cap using a hard material canbe prevented, thus improving the safety of the bottle sufficientlywithout failure.

A tenth invention has an arrangement in which split grooves are providedat least at the lower end of the attaching cylinder of the pour cap, andthe joining strength of the pour-cap main body to the bottle mouthcylinder is set so as to be broken off by hand in the range of notturning free relative to the bottle mouth cylinder, in addition to thearrangement of the synthetic-resin screw cap according to the third,fourth, fifth, sixth, seventh, or ninth invention.

According to this invention, the joining strength of the pour-cap mainbody to the bottle mouth cylinder can accurately be set in anappropriate range on the basis of the number of the split grooves andthe length and shape of the grooves; and when the screw cap serving as apour cap constituted by the pour-cap main body and the outer cap isdivided from the bottle mouth cylinder for collection, the bendingdeformation of the attaching cylinder in the direction to increase thediameter can be set in an appropriate range against the external forceto divide the pour-cap main body from the bottle mouth cylinder bybreaking by hand.

An eleventh invention has an arrangement in which a locking ridge isprovided at the lower end of the inner peripheral surface of theattaching cylinder of the pour-cap main body fitted on the bottle mouthcylinder, which is locked across the locking circumferential ridgeprovided around the outer periphery of the opening of the bottle mouthcylinder, and the locking ridge of the attaching cylinder of thepour-cap main body has an intermittent circumferential ridge structureas the means for setting the joining strength of the pour-cap main bodyto the bottle mouth cylinder, in addition to the arrangement of thesynthetic-resin screw cap according to the third, fourth, fifth, sixth,seventh, or ninth invention.

According to this invention, since the locking ridge provided at thelower end of the inner peripheral surface of the attaching cylinder ofthe pour-cap main body, which is locked across the lockingcircumferential ridge of the bottle mouth cylinder, has an intermittentcircumferential ridge structure, the attaching cylinder becomes thin bythe amount corresponding to the absent locking ridge, thus being easilyincreased in diameter. Therefore when the pour-cap main body is dividedfrom the bottle mouth cylinder for collection, the bending deformationof the attaching cylinder in the direction to increase the diameter canbe set in an appropriate range against the external force to divide thepour-cap main body by breaking by hand.

The intermittent circumferential ridge structure means a circumferentialridge structure having absent portions in opposite two positions or inplural positions with regular intervals by eliminating the locking ridgewith the circumferential ridge structure.

A twelfth invention has an arrangement in which a spacing into which theend of a hard material such as a coin can be inserted is formed betweenthe lower edge of the attaching cylinder of the pour-cap main body andthe neck ring, in addition to the arrangement of the synthetic-resinscrew cap according to the third, fourth, fifth, sixth, seventh, eighth,tenth, or eleventh invention.

According to this invention, even a weak person can easily divide thepour-cap main body from the bottle mouth cylinder by break-opening usinga familiar hard material such as a coin.

A thirteenth invention has an arrangement in which the pour-cap mainbody and the outer cap are colored different, in addition to thearrangement of the synthetic-resin screw cap according to the third,fourth, fifth, sixth, seventh, ninth, tenth, eleventh, or twelfthinvention.

According to this invention, since the breakable pieces are broken andthe sealing ring of the outer cap moves downwards to the downward limit,the lower portion of the attaching cylinder of the different-colorpour-cap main body is exposed under the outer cap to stand out clearly;therefore, the pilfer-proof function is exhibited more effectively.

A fourteenth invention has an arrangement in which the pour spout formedat the pour-cap main body is a pull-open pour spout opened by breakingand removing an unplug section having a pull ring or the like, which isdivided by breakable grooves that constructs a closed loop in a sealingwall that is a bottom wall of a pour cylinder provided so as to guidethe pouring of a contents liquid, in addition to the arrangement of thesynthetic-resin screw cap according to the third, fourth, fifth, sixth,seventh, ninth, tenth, eleventh, twelfth, or thirteenth invention.

According to this invention, the bottle can be closely sealed reliablyand firmly until the opening of the pour spout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general perspective view of a first embodiment, showing astate before a screw cap and a bottle mouth cylinder is joined.

FIG. 2 is a half longitudinal sectional view of a cap main body, shownin FIG. 1, showing a state before it is unscrewed.

FIG. 3 is a half longitudinal sectional view of a second embodiment of ascrew cap, showing a state before a cap main body is unscrewed.

FIG. 4 is a half longitudinal sectional view of the cap main body, shownin FIG. 1, showing a state after the cap main body has been unscrewed.

FIG. 5 is a general perspective view of a fifth embodiment of a screwcap, showing a state before a pour cap constituted by a pour-cap mainbody and an outer cap is joined.

FIG. 6 is a half longitudinal sectional view of the outer cap, shown inFIG. 5, showing a state before the outer cap is unscrewed.

FIG. 7 is a half longitudinal sectional view of the outer cap, shown inFIG. 5, showing a state after the outer cap has been unscrewed.

FIG. 8 is a partially enlarged front view of a first embodiment of theessential parts.

FIG. 9 is a partially enlarged front view of a second embodiment of theessential parts.

FIG. 10 is a partially enlarged front view of a third embodiment of theessential parts.

FIG. 11 is a partially enlarged front view of a fourth embodiment of theessential parts.

FIG. 12 is an explanatory view for describing the operation.

FIG. 13 is a general perspective view of the fourth embodiment of thescrew cap with a cap main body divided.

FIG. 14 is a general perspective view of a fifth embodiment of a screwcap with an outer cap divided.

FIG. 15 is a partially enlarged front view of the fifth embodiment ofthe essential parts.

FIG. 16 is a general perspective view of a sixth embodiment of a screwcap with a cap main body divided.

FIG. 17 is a general perspective view of a seventh embodiment of a screwcap with an outer cap divided.

FIG. 18 is a general perspective view of an eighth embodiment of a screwcap, showing a pour-cap main body.

FIG. 19 is a bottom view of a ninth embodiment of a screw cap, showing apour-cap main body.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described hereinafter withreference to the drawings.

First, as a first embodiment and a second embodiment, a synthetic-resinscrew cap 1, shown in FIGS. 1 to 4, will be described which includes abottle mouth cylinder 18 itself as a pour spout of a bottle, to which acap main body 2A serving as a cap section is directly joined.

The synthetic-resin screw cap 1 of the first embodiment, shown in FIG.1, is a solid molding made of a polypropylene resin or a low-densitypolyethylene resin, and is formed such that the cap main body 2A servingas a cylindrical cap section having a top and a short cylindricalsealing ring 11 are integrally connected through a plurality of easilybreakable pieces 7.

The cap main body 2A serving as a cap section is constructed incylindrical form having a top such that the upper end of a cylindricalwall 3A serving as a cylindrical wall section, which is screwed on thebottle mouth cylinder 18 having a helical ridge 19A around the outerperipheral surface through a helical ridge 5 on the inner peripheralsurface, is closed with a top plate 4 having a cylindrical plug piece 6hung from the lower surface.

As shown in FIG. 2, the cylindrical plug piece 6 is closely fitted inthe opening of the bottle mouth cylinder 18 directly, having a packing17 mounted outside the cylindrical plug piece 6 and at the lower surfaceof the top plate 4 facing the upper end face of the bottle mouthcylinder 18. In the second embodiment of FIG. 3, since an inside plug 23with a pour cylindrical piece 24 constituting a pour spout of the bottleis joined to the opening of the bottle mouth cylinder 18, thecylindrical plug piece 6 has the pour cylindrical piece 24 of the insideplug 23 fitted therein closely.

A sealing ring 11 connected to the lower end of the cylindrical wall 3Athrough easily breakable pieces 7 has a height to form a spacing s inwhich the end of a hard material such as a coin can be inserted betweenit and a neck ring 21 of the bottle mouth cylinder 18 with the cap mainbody 2A joined to the screw limit of the bottle mouth cylinder 18, andalso has a second locking section 12 projecting from the innerperipheral surface thereof and locked from below across a first lockingsection 20A, the first locking section 20A being provided around theouter peripheral surface of the bottle mouth cylinder 18 positionedlower than the helical ridge 19A, with the outer end arranged outsidethe helical ridge 19A.

When the sealing ring 11 is separated from the bottle mouth cylinder 18,the end of a familiar hard material such as the periphery of a coin isinserted into the spacing s between the sealing ring 11 and the neckring 21, and the sealing ring 11 is forcedly opened in the direction toincrease the diameter, thus allowing easy division.

Although both of the first locking section 20A and the second lockingsection 12 have a ridge structure in the first embodiment and the secondembodiment, shown in FIGS. 2 and 3, it is not limited to that, but maybe, for example, a recessed groove structure in which one engages withthe other.

Next, as a third embodiment, a synthetic-resin screw cap 1, shown inFIGS. 5 to 7, will be described which is a pour cap constituted by apour-cap main body 25 fitted on the bottle mouth cylinder 18 serving asa pour spout of the bottle, and an outer cap 2B serving as a capsection.

The pour-cap main body 25 constituting the pour spout of the bottle isconstructed such that it is fitted on the bottle mouth cylinder 18; ascrew cylinder 29 having a helical ridge 19B grooved in the outerperipheral surface is arranged, through an inward-flanged top wall 28 onthe upper end of a attaching cylinder 26, which is formed to a height toform a spacing into which the end of a hard material, such as theperiphery of a coin, can be inserted; a pour cylinder 32 having a bottomhaving the upper end enlarged in diameter like a trumpet is connected tothe upper end of the screw cylinder 29 through an inward flanged piece31; and an unplug section 34 having a pull-ring or the like and dividedby a breakable groove 35 formed into a closed loop is formed on asealing wall 33 that is a bottom wall of the pour cylinder 32.

A attaching cylinder 26 fitted on the bottle mouth cylinder 18 includesa locking ridge 27 at the lower end of the inner peripheral surface forgetting over and locking a locking circumferential ridge 22 providedaround the outer periphery of the opening of the bottle mouth cylinder18 to constitute a portion constructing the function of locking to thebottle mouth cylinder 18, and also forms a first locking section 20Bshaped like a circumferential ridge around the outer peripheral surfaceof a portion facing the locking circumferential ridge 22, which ispositioned on the upper outer peripheral surface adjacent to the lockingridge 27.

A sealing cylindrical piece 30 extending and hung from the screwcylinder 29 is closely fitted on the bottle mouth cylinder 18, therebymaking the pour-cap main body 25 join to the bottle mouth cylinder 18sufficiently closely.

The outer cap 2B serving as a cap section is formed such that a maincylinder 3 a to be screwed on the screw cylinder 29 of the pour-cap mainbody 25 is hung from the periphery of the top plate 4 that hangs thecylindrical plug piece 6 to be closely fitted in the opening end of thepour cylinder 32 of the pour-cap main body 25; the outer cylinder 3B tobe fitted on the attaching cylinder 26 via an outer flanged piece 3 c ishung from the lower end of the main cylinder 3 a; and the sealing ring11 is connected to the lower end of the outer cylinder 3B via the easilybreakable piece 7, the sealing ring 11 having the ridge-shaped secondlocking section 12, at the inner peripheral surface, to be locked frombelow across the first locking section 20B. The main cylinder 3 a, theouter flanged piece 3 c, and the outer cylinder 3B constitute acylindrical wall section of the outer cap 2B.

Since the sealing ring 11 has a width from the first locking section 20Bto the neck ring 21 and an inner diameter larger than the outer diameterof the neck ring 21, the upper end thereof is substantially in contactwith the first locking section 20B, and the lower end is opposed to theouter peripheral surface of the neck ring 21 in the unsealed state ofFIG. 6, thus allowing it to be dropped and displaced withoutinterference of the neck ring 21 when the breakable pieces 7 are broken.

The upper end of the sealing ring 11 provided at the lower end of theouter cap 2B is substantially in contact with the first locking section20B of the pour-cap main body 25 constituting a pour spout, therebypreventing deformation of the attaching cylinder 26 by an increase inthe diameter. Therefore, even when the attaching cylinder 26 is formedthin so as to easily be separated from the bottle mouth cylinder 18,frequent diameter enlargement and deformation of the attaching cylinder26 can be prevented to achieve and maintain stable joining of thepour-cap main body 25 to the bottle mouth cylinder 18, and also thespacing formed between the attaching cylinder 26 and the neck ring 21 iscovered, thereby disabling unjust process of directly and forciblyopening the pour-cap main body 25.

Also, the minimum inner diameter of the sealing ring 11 including thesecond locking section 12 is set larger than the outer diameter of theneck ring 21; therefore, when the breakable pieces 7 are broken, thesealing ring 11 can be displaced downwards lower than the neck ring 21owing to its own weight, as shown in FIG. 7, thereby preventing theoccurrence of a trouble in that the second locking section 12 is caughtby the neck ring 21, and so the upper end of the sealing ring 11sheathes the lower end of the attaching cylinder 26 to disable thediameter enlargement and deformation of the attaching cylinder 26.

FIG. 8 shows the first embodiment of the essential parts of the presentinvention, which includes a plurality of first combinations of firststopping sections 8 and first pressing slopes 9 at the lower end of thecylindrical wall 3A or the outer cylinder 3B, which forms thecylindrical wall section of the cap main body 2A or the outer cap 2Bserving as a cap section, respectively. A plurality of secondcombinations 15 of second stopping sections 13 for the first stoppingsections 8 and second pressing slopes 14 for the first pressing slopes 9is provided at the upper end of the sealing ring 11. In FIG. 8, one ofthe first combinations 10 is formed into a protrusion; on the otherhand, one of the second combinations 15 is formed into a recessed shapebetween two protrusions.

In the second embodiment of the essential parts, shown in FIG. 9, one ofthe first combinations 10 is formed into a recessed shape; on the otherhand, one of the second combinations 15 is formed into a protrusion.

In the third embodiment of the essential parts of the present invention,shown in FIG. 10, one of the first combinations 10 is formed into aprotrusion; on the other hand, one of the second combinations 15opposite thereto is formed into a recessed shape, contrarily to thesecond embodiment of the essential parts shown in FIG. 9.

In the first embodiment of the essential parts, shown in FIG. 8, arelatively large spacing is formed between the cylindrical wall 3A orthe outer cylinder 3B serving as a cylindrical wall section and thesealing ring 11, thus allowing decreasing the amount of a syntheticresin material required for molding the cap main body 2A or the outercap 2B correspondingly. On the other hand, in the case of the second andthird embodiments of the essential parts, shown in FIGS. 9 and 10, theeasily breakable pieces 7 can be formed short, thus facilitating moldingcorrespondingly.

The first stopping sections 8 and the second stopping sections 13disable the rotating displacement of the sealing ring 11 in the unscrewdirection relative to the cap main body 2A or the outer cap 2B by themutual abutment to integrally rotate them in the screwing direction whenthe cap main body 2A or the outer cap 2B serving as a cap section isfirst screwed on the bottle mouth cylinder 18 or the pour-cap main body25 serving as a pour spout of the bottle, thereby allowing the secondlocking section 12 to forcibly get over the first locking section 20A orthe first locking section 20B.

In a fourth embodiment of the essential parts of the present invention,shown in FIG. 11, a protrusion 16 is provided at the bottom of the firstcombinations 10 that is the lower surface of the cylindrical wall 3A orthe outer cylinder 3B so as to face the upper surface of the sealingring 11, for decreasing the spacing between the cylindrical wall 3A orthe outer cylinder 3B and the sealing ring 11. The protrusion 16 abutsagainst the upper surface of the sealing ring 11 when the cap main body2A or the outer cap 2B is first screwed on the bottle mouth cylinder 18or the pour-cap main body 25 to ensure a stroke between the cylindricalwall 3A or the outer cylinder 3B and the sealing ring 11, therebypreventing the easily breakable pieces 7 from bending to be brokenbecause of a decrease in the stroke.

Even if the cap main body 2A or the outer cap 2B bends slightly when thecap main body 2A or the outer cap 2B is screwed on the bottle mouthcylinder 18 or the pour-cap main body 25, the protrusion 16 presses theupper surface of the sealing ring 11, and the second locking section 12gets over the first locking section 20A or the first locking section 20Bwithout fail to lock the first locking section 20A or the first lockingsection 20B from below.

The first pressing slopes 9 and the second pressing slopes 14(hereinafter, refer to FIG. 12) are brought into contact with each otherat a tilt angle b that is an acute angle larger than the lead angle a ofthe helical ridge 5 and the helical ridge 19A or the helical ridge 19Bwhen the screw cap 1 is first turned in the unscrew direction.Accordingly, when the first pressing slopes 9 move in the direction of ealong the lead angle a in the turning range of the screw cap 1 where theabutment of both the pressing slopes is completed (the breakable pieces7 have been broken at the start of the turning range), the secondpressing slopes 14 are pushed down to move downwards in the direction off.

In other words, the cap main body 2A or the outer cap 2B moves upwardsby the distance c along the lead angle a; on the other hand, the sealingring 11 cannot move upwards by the locking of the second locking section12 to the first locking section 20A or the first locking section 20B.Therefore, the sealing ring 11, which cannot turn with the cap main body2A or the outer cap 2B, is pushed down relative to the cap main body 2Aor the outer cap 2B by a distance d larger than the distance c along thetilt angle b.

As described above, the sealing ring 11 is forcedly pushed down by thedistance d from the cap main body 2A or the outer cap 2B. Therefore,even if the sealing ring 11 is adhered due to damp or the like to thefirst locking section 20A of the bottle mouth cylinder 18 or the firstlocking section 20B of the pour-cap main body 25 in the position wherethe second locking section 12 is locked to the first locking section 20Aor the first locking section 20B, the sealing ring 11 is surelyseparated from the first locking section 20A or the first lockingsection 20B, and moves downwards owing to its own weight.

For the first combinations 10 of the first stopping sections 8 and thefirst pressing slopes 9 and the second combinations 15 of the secondstopping sections 13 and the second pressing slopes 14, it is easiest toprovide a plurality of ones having the same structure at-intervals alongthe circumference, as in the fourth embodiment of the screw cap of FIG.13 or the fifth embodiment of the screw cap of FIG. 14.

Also, as in the fifth embodiment of the essential parts of the presentinvention, shown in FIG. 15, when an opposed pair of first combinations10 and 15 is arranged in the form of wave in the circumferentialdirection, the shape of the lower end of the cylindrical wall 3A or theouter cylinder 3B and the shape of the upper end of the sealing ring 11have high symmetry, thus improving the appearance and the design.

On the other hand, as in a sixth embodiment of a screw cap of FIG. 16 ora seventh embodiment of a screw cap of FIG. 17, a pair of opposedcombinations is formed of a combination of a protrusion that is slightlylong in the circumferential direction and a recessed portion, so that acut taper for a separate die can be formed at the circumferentially longjoined portion, thereby allowing constructing a cavity mold of a moldassembly for molding the cap main body 2A and the outer cap 2B with asimple split mold without the requirement for a slide core.

When the screw cap constituted by the pour-cap main body 25 and theouter cap 2B is divided from the bottle mouth cylinder 18, the pour-capmain body 25 may be forcedly broken off with the outer cap 2B screwedthereon; however, the screw cap 1 that is a pour cap can easily bedivided by inserting the end of a familiar hard material such as theedge of a coin into the spacing between the attaching cylinder 26 andthe neck ring 21.

Also, as in the pour-cap main body 25 of an eighth embodiment of thescrew cap, shown in FIG. 18, split grooves 27 a are provided at thelower end of the attaching cylinder 26 having the locking ridge 27; andthe joining strength of the pour-cap main body 25 to the bottle mouthcylinder 18 is set so as to allow breaking-off by hand in the range ofnot turning free relative to the bottle mouth cylinder 18.

For the attaching cylinder 26, the split grooves 27 a are increased indiameter by the action of the breaking-off by hand, so that theattaching cylinder 26 bends to be deformed sufficiently; therefore, evena weak person can smoothly divide by breaking off the bottle mouthcylinder 18 of the screw cap 1 that is a pour cap constituted by thepour-cap main body 25 and the outer cap 2B.

When the split grooves 27 a are formed, it is necessary to design notonly the number but also the length, the width and so on inconsideration of the structure of the whole bottle and the condition ofuse so that the joining strength of the pour-cap main body 25 to thebottle mouth cylinder 18 is in an appropriate range and also in a rangeto allow the pour-cap main body 25 to be broken off by the weak actionof breaking-off.

As in the pour-cap main body 25 that is-a ninth embodiment of a screwcap, shown in FIG. 19, with a structure in which the locking ridge 27 ofthe attaching cylinder 26 intermittently projects around the periphery,the attaching cylinder 26 becomes thin only at portions where thelocking ridge 27 is absent, thus easily increasing in diameter.Accordingly, even a weak person can smoothly break off the screw cap 1from the bottle mouth cylinder 18.

The locking ridge 27 must have an intermittent circumferential ridgestructure in which the locking ridge 27 is eliminated at two oppositeportions or a plurality of portions with regular intervals inconsideration of the condition of use and so on so that the joiningstrength of the pour-cap main body 25 to the bottle mouth cylinder 18 isin an appropriate range and also in a range to allow the pour-cap mainbody 25 to be broken off by the weak action of breaking-off.

In addition, it is also possible to easily divide the pour-cap main body25 from the bottle mouth cylinder 18 by inserting a familiar hardmaterial such as a handle of a spoon into the opening of the unplugsection 34 after pulling a pullring, catching one end of the hardmaterial in the inward-flanged sealing wall 33, and lifting up thepour-cap main body 25 by the action of lever of the hard material.

Industrial Applicability

As described above, it is a technical object of the present invention todrop and displace a portion of a pilfer-proof cap, which corresponds toa pilfer-proof base section, when a lid main body is unscrewed bybreaking a portion corresponding to a rib, thus exhibiting thepilfer-proof function without fail.

1. A synthetic-resin screw cap, comprising: a pour-cap main body havingan attaching cylinder that slides over and is fitted on a bottle mouthcylinder having a neck ring and forming a pour spout by being closelyfitted; an outer cap serving as a cylindrical cap section, outercylinder, and with a top for opening and closing the pour spout, whereina first locking section is formed around an outer peripheral surface ofthe attaching cylinder; and a sealing ring is integrally connected to alower end of an outer cylinder through a plurality of easily breakablepieces, the outer cylinder serving as a cylindrical wall section of theouter cap to be fitted on the attaching cylinder in a closed state, andthe sealing ring having a second locking section to be slid over andlocked with the first locking section of the pour cap main body, thesecond locking section being positioned between the first lockingsection and the neck ring when the cap section is screwed onto the pourspout, wherein a plurality of second pressing slopes is disposed on anupper end of the sealing ring so that the plurality of second pressingslopes is closely opposed to a plurality of first pressing slopesdisposed at the lower end of the outer cylinder so as to slidably abutagainst the plurality of first pressing slopes from an unscrewingdirection and at a tilt angle that is a larger acute angle than a leadangle of a helical ridge of the pour-cap main body.
 2. A synthetic-resinscrew cap according to claim 1, wherein the cylindrical wall sectionincludes first stopping sections in combination with the first pressingslopes, and the sealing ring includes second stopping sections incombination with the second pressing slopes, the second stoppingsections being closely opposed to the first stopping sections so as notto get over them from the screwing direction.
 3. A synthetic-resin screwcap according to claim 2, wherein one of a first combination of thefirst stopping sections and the first pressing slopes and a secondcombination of the second stopping sections and the second pressingslopes is formed into a protrusion, and the other is formed into arecess into which the protrusion is inserted.
 4. A synthetic-resin screwcap according to claim 3, wherein each of the first combinations and thesecond combinations, one of which is formed into a protrusion and theother is formed into a recess, is arranged in wave form in thecircumferential direction.
 5. A synthetic-resin screw cap according toclaim 1, wherein either one of the lower end of the cylindrical wallsection and the upper end of the sealing ring has a protrusion extendingtoward the other for decreasing the spacing between the cylindrical wallsection and the sealing ring.
 6. A synthetic-resin screw cap accordingto claim 1, wherein a spacing into which an end of a hard material canbe inserted is formed between a lower edge of the cylindrical wallsection and the neck ring provided at a lower part of an outerperipheral surface of the bottle mouth cylinder.
 7. A synthetic-resinscrew cap according to claim 1, wherein a width of the sealing ring isset to a value at which the lower end almost reaches the neck ring ofthe bottle mouth cylinder while being fitted on the bottle mouthcylinder.
 8. A synthetic-resin screw cap according to claim 1, whereinsplit grooves are provided at least at a lower end of the attachingcylinder, and a joining strength of the pour-cap main body to the bottlemouth cylinder is set so as to be broken off by hand in a range of notturning free relative to the bottle mouth cylinder.
 9. A synthetic-resinscrew cap according to claim 1, wherein a locking ridge is provided at alower end of an inner peripheral surface of the attaching cylinder to befitted on the bottle mouth cylinder, the locking ridge being lockedacross the locking circumferential ridge provided around an outerperiphery of an opening of the bottle mouth cylinder, and the lockingridge of the attaching cylinder has an intermittent circumferentialridge structure as the means for setting a joining strength of thepour-cap main body to the bottle mouth cylinder.
 10. A synthetic-resinscrew cap according to claim 1, wherein a spacing into which an end of ahard material such as a coin can be inserted is formed between a loweredge of the attaching cylinder and the neck ring provided at a lowerpart of an outer peripheral surface of the bottle mouth cylinder.
 11. Asynthetic-resin screw cap according to claim 1, wherein the pour-capmain body and the outer cap are colored different.
 12. A synthetic-resinscrew cap according to claim 1, wherein the pour spout formed at thepour-cap main body serving as a pour cap section is a pull-open pourspout opened by breaking and removing an unplug section, which isdivided by a breakable groove constructing a closed loop in a sealingwall that is a bottom wall of a pour cylinder provided in order to guidethe pouring of a contents liquid.